Background/Objectives: Obesity is associated with chronic systemic inflammation and elevated levels of inflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and C-reactive protein (CRP). Weight loss through lifestyle interventions can reduce inflammation in adults with obesity. Time-restricted eating (TRE) and calorie restriction (CR) are two popular diet interventions that can produce clinically significant weight loss. However, to date, no studies have directly compared the effects of TRE versus CR on inflammatory cytokines in adults with obesity. Methods: Here, we performed a secondary analysis on a recently published study to compare the long-term (12-month) effects of TRE versus CR on key inflammatory cytokines. Results: We found that while TRE and CR produced similar amounts of weight loss (4-5% from baseline), no statistically significant changes in circulating levels of TNF-alpha, IL-6, and CRP were noted in the TRE or CR groups, compared to the controls, by month 12. However, we did observe that circulating CRP levels were positively related to body weight, visceral fat mass, and insulin resistance, while IL-6 and TNF-alpha were not related to any metabolic marker. Conclusions: Thus, TRE and CR may not affect key inflammatory mediators with 4-5% weight loss, but more research is warranted.
Keywords: C-reactive protein (CRP); calorie restriction; inflammation; interleukin-6 (IL-6); intermittent fasting; obesity; time-restricted eating; tumor necrosis factor alpha (TNF-alpha); weight loss.